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NV4500 Failure this AM

rcamacho

rcamacho

1/2 ton status
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My NV4500 went boom this morning on the way to ski at Snoqualmie with my wife and daughter in tow. :(

I was driving in fifth gear at the time and with a loud bang and grinding the truck was done. No motivation in any gear, bad sounds.

Q: Does this sound like a 5th gear failure or an input failure?
Q: I'm running an AA housing. How do I identify which series transmission it is?
Q: Recommendations on NV4500 replacements and parts?
 
rcamacho said:
My NV4500 went boom this morning on the way to ski at Snoqualmie with my wife and daughter in tow. :(

I was driving in fifth gear at the time and with a loud bang and grinding the truck was done. No motivation in any gear, bad sounds.

Q: Does this sound like a 5th gear failure or an input failure?
Q: I'm running an AA housing. How do I identify which series transmission it is?
Q: Recommendations on NV4500 replacements and parts?
Click to expand...


Don't know any answers; just want to send my condolences.

Look at the bright side: Time to update to a NV5600 :D :bow: :bow: !!
 
Yeah, you've had a 5th gear failure. NV4500s are known for that. The nut that is suppost to hold the 5th gear on works loose, and eventually drops right off, allowing the 5th gear to fall off as well, which causes a pretty catastrophic failure like you experienced.

Good news is that the 5th gear is in it's own sort of housing, and there is a possiblity the rest of your transmission's gears are alright. Bad news is that you'll need a new mainshaft with an updated 5th gear retainer, and gears for 5th on both the mainshaft, and countershaft.

Only way to know for sure is to take the thing apart, and take a look...
 
Nope, 5th gear failure results in the loss of 5th gear only. The other 4 should work just fine. Sounds exactly like what happened to the first NV4500 that was in that truck...catastrophic input gear failure. Bill figured the first one was caused by low lube levels. Two seemingly identical failures tells me there may be something else going on. Could be a bad pilot causing the input to eventually destroy the bearing, which leads to catastrophic failure.

For what it's worth the first NV4500 in that truck was a '95 4WD diesel version. I tend to think Bill replaced it with the same thing. IIRC he bought both from GM over the parts counter. 5th gear failure is very unlikely with that version because of the damper between 5th gear and the mainshaft nut.

Rene
 
Forgot to add that I got all my NV4500 replacement parts through Kyle at Northwest Fab. His prices were very good, but there were a lot of parts needed. My countershaft was destroyed, as was the input gear, and all the synchro's were garbage too.

Rene
 
The front bearing failure seems to be one of the more common 4500 problem areas. Some of the Dodge guys run an extra 1/2-1 QT of Syntorq to make sure it stays lubed.
 
tRustyK5 said:
Nope, 5th gear failure results in the loss of 5th gear only. The other 4 should work just fine. Sounds exactly like what happened to the first NV4500 that was in that truck...catastrophic input gear failure. Bill figured the first one was caused by low lube levels. Two seemingly identical failures tells me there may be something else going on. Could be a bad pilot causing the input to eventually destroy the bearing, which leads to catastrophic failure.

For what it's worth the first NV4500 in that truck was a '95 4WD diesel version. I tend to think Bill replaced it with the same thing. IIRC he bought both from GM over the parts counter. 5th gear failure is very unlikely with that version because of the damper between 5th gear and the mainshaft nut.

Rene
Click to expand...

Thanks Rene.
I'll pull the trans later this week hopefully. If not the pilot bushing I'd suspect the bellhousing was not aligned to the crankshaft center. I'll count the splines and pull the numbers off the trans.
 
Look at the bright side: Time to update to a NV5600 :D :bow: :bow: !![/quote]

Hmm, aside from it being horrendously expensive can it be adapted to a bbc?

Heck, I'm tempted to run an SM465 given the cost of repairing or replacing the 4500....
 
NV5600: Horrendously spendy, horrendously heavy, horrendously large...and never offered in a GM app. The GM 6 speed was the ZF-S6-650 offered behind the 8.1's and the Duramax's. Also spendy, hard to find etc etc.

Rene
 
If you do go SM465, lemme know, as I'd be interested in the AA bellhousing, I'm planning on swapping a 93 NV4500 into my truck, and was thinking of trying to keep the stock bellhousing.
 
Time to Rand R the 4500. I would keep the 4500, the 5600 is SOOOO much larger, plus they were only made for a few years, so the price of one is going to be high, the input is not correct, and same with the bellhousing (which is intregal). Definetly more then 5th gear failure though. You should be able to pull the floor pan and the top cover to check it out.
 
Update 1/2/07

Happy new year everyone!

Well I got industrious and pulled everything off except the transmission this evening. The NP208 was fine (darn). The NV4500 is definitely fried. It just grinds gears manually turning the output shaft in any gear.

Hopefully I'll have time to pull the transmission tomorrow and check the carnage.

According to "tRustyK5" this is the second NV4500 this rig has been through with input shaft failure. I'll take the time to make sure the AA adapter is true and concentric before replacement. Id' the case as a 92-95 GM series, probably with the deep gearset.
 
I'd be very interested to see the results of the bell measuring. I have the same Advance Adaptors bell. :crazy:

I did find that my initial theory was not valid. I thought maybe the pilot diameter of the NV4500 and the SM465 might be slightly different, but have now found a few sources confirming that both are .590" pilot diamters.

You might want to do a search for posts by "Sparky87K5". That was Bill's user name here when he still owned your truck. You might find out a bit more info about it reading through his old posts.

Rene
 
Its definetly salvagable. New input, bearings and dependig what year tranny you have you can either change the gear on the counter shaft, or replace the whole counter shaft, either way, definetly salvageable.
 
I think Kyle can get pretty much any tranny hard parts.

FWIW the same failure on my NV4500 scorched the synchro's too.

I ended up getting the master rebuild kit which was all the bearings and seals, the small parts kit which includes all the little stuff like shift fork pads, shims etc etc. Countershaft, mainshaft nut, input shaft, 3-4 sychro assembly (the whole thing, not just the brass stuff) and all the rest of the synchros except for the 2-3 synchro which appeared to be in perfect shape. Appeared being the key word, as the only gear I can't shift into quickly is third now. As annoying as it is I'm pulling my tranny back out soon and replacing that synchro.

Rene
 
This is what my NV5600 currently looks like. OD bearing failure, took out a gear maybe two and some other collateral damage. I need to track down parts.

Thanks I'll try Kyle at NWF


NV5600001.jpg

NV5600003.jpg

NV5600002.jpg
 
No these never came in a GM. this is out of an '01 Dodge. and going into my '98.5 Dodge to replace the NV4500 thats currently there.
 
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